Is Earth a sphere?

Morrus · Aug 26, 2013

gamerprinter said:
I think the term "sphere" is clear enough, without a need for "perfect" to added in front. It is either a sphere or not. Consider a four sided object, if equal length lines with 90 degree corners, I'd call that a square. If lines or angles are off, I wouldn't call it squarish or almost a square. I'd call it a parallelogram, a rhombus, a trapezoid or a quadrilateral shape - or whatever it happened to be.

Being an artist, I perceive my world visually, and exact definitions when they are available should be used even in simple conversation to describe what we see. I'm not trying to be anal, I just call things as I see them and call them by their proper names, if I know them.

So you would never call anything a sphere, give that a perfect sphere does not exist in the universe (to our knowledge)? Is it just a word you would never, ever use?

[Physicists can correct me if I'm wrong about that - maybe singularities/black holes or something form perfect spheres!]

gamerprinter · Aug 26, 2013

As I said, I'm an artist, I can create a sphere in 3D. Though it does not exist in the non-virtual world, doesn't mean it doesn't exist. Let me be clear, if the distances between the poles was equidistant to opposite points on the equator (not having a .003 difference), I'd call it a sphere, even though there are deep places in the ocean and great heights in the mountains. It doesn't have to be perfect to be called a sphere, but if oblate spheroid is a closer definition of the earth than a sphere, I'd use that term.

I'd also call a spherically shaped man-made objects spheres. A golf ball has divots in it making it not a perfect sphere, but show me a photo of a golf ball and one of the earth and ask which is the sphere? I'd point to the golf ball.

I consider the theoretical concepts as existing as well. The idea of a perfect sphere can be imagined, so in that sense it exists.

I'll bet a singularity is much closer to an exact sphere to anything else as far as heavenly bodies go. How about a dwarf star? The gravitational forces are so great, perhaps having no shape alteration because of polar spin.

Umbran · Aug 26, 2013

Morrus said:
So you would never call anything a sphere, give that a perfect sphere does not exist in the universe (to our knowledge)? Is it just a word you would never, ever use?

[Physicists can correct me if I'm wrong about that - maybe singularities/black holes or something form perfect spheres!]

If a black hole is spinning (which it likely is, as the star it came from was probably spinning and there's no solidly accepted mechanism for it to shed the angular momentum as it dies), then it, too, will be a oblate sphereoid.

Context matters. Here, on EN World, I'm one of the science details guys - that forms a chunk of my social context. So, when a science question comes up, I will tend to give a more precise answer over a less precise one. That doesn't mean I'll never refer to something as a sphere, just in these types of questions I have a leaning to the details.

Hand of Evil · Aug 26, 2013

The best term would be globe but that is a model of the earth (if you don't want to go planet, you bunch of gas giant supporters)

Janx · Aug 26, 2013

Umbran said:
If a black hole is spinning (which it likely is, as the star it came from was probably spinning and there's no solidly accepted mechanism for it to shed the angular momentum as it dies), then it, too, will be a oblate sphereoid.

Context matters. Here, on EN World, I'm one of the science details guys - that forms a chunk of my social context. So, when a science question comes up, I will tend to give a more precise answer over a less precise one. That doesn't mean I'll never refer to something as a sphere, just in these types of questions I have a leaning to the details.

So is it always appropriate to respond in the literal and technically precise, or can you dumb it down a a little some times?

The reality is, Bullgrit was running an experiment of sorts. He chose a vague and imprecise term to see how people like you an me respond (no harm in that, those experiments are fun). I certainly smelled this was an experiment when I saw it, and I suspect so did you.

I'm curious if folks like you and myself can recognize when a situation doesn't call for sciency Mr. Right to chime in, and just go along with a basic answer?

darjr · Aug 26, 2013

[MENTION=8835]Janx[/MENTION];
I don't want it to be that simple. I'd like to get this interplay when questions like this come up. I think it'd do the whole sphere (squished or not) good if more of this kind of conversation could be had.

Janx · Aug 26, 2013

darjr said:
[MENTION=8835]Janx[/MENTION];
I don't want it to be that simple. I'd like to get this interplay when questions like this come up. I think it'd do the whole sphere (squished or not) good if more of this kind of conversation could be had.

Certainly in the context that "It seems like Bullgrit's asking a trick question..." framework, that makes sense.

but in other context?

What if Bullgrit was asking "is the earth round or flat?" because he was responding to somebody who thought the moon landing was faked and the international dateline is where the drop-off the edge is (that's why Oceanic 815 disappeared off the map, you know).

to me, some of these responses can start to feel more like "look at how much smarter I am compared to the rest of you louts"

While it's not a good thing that school children don't express interest in learning and don't want to appear to be "smart", it is also prideful and denigrating to be the kid who HAS to raise his hand to answer every question to show the rest of the class how smart he is.

As Douglas Adams observed, nobody likes a smart ass.

tomBitonti · Aug 26, 2013

Not sure if this is the best analysis. Fudging somewhat about what would be perceptible. I'm using a half width of a 0.1 mm line as a limit. I suspect that is smaller than necessary, but don't have anything to go on to set a different limit.

For the Earth:

Equatorial Radius: 6.378 x 10^3 km

Polar Radius: 6.357 x 10^3 km

0.021 x 10^3 km (21 km)

21 km / 6,378 km = 0.0033 = 0.3%

1 part in 333

Assuming that a very fine 0.2mm mechanical pencil will generate a 0.1 mm line, 33.3 mm is 3.3 cm. Slightly more than 1 in.

Would be interesting to ask how that relates to perception: At what scale would the oblateness be perceptible?

Thx!

TomB

Bullgrit · Aug 26, 2013

Janx said:
The reality is, Bullgrit was running an experiment of sorts. He chose a vague and imprecise term to see how people like you an me respond (no harm in that, those experiments are fun). I certainly smelled this was an experiment when I saw it, and I suspect so did you.

An experiment, yes. But one for discussion. Although I don't think I used a vague and imprecise term. "Sphere" is pretty specific and precise -- as the responses in this thread show.

Janx said:
Certainly in the context that "It seems like Bullgrit's asking a trick question..." framework, that makes sense.

This wasn't a trick question. There was no trickery or misdirection, and no point to be made. No one who answered either way should feel in anyway tricked. It's not like I had the "correct" answer, and just wanted to spring it on anyone who answered "wrong."

Morrus said:
And given Bullgrit has now defined the context as a not-really-a-context-just-a-medium, the only real answer is "I guess, if you want". Or, in short, the question needs a context to have any meaning, and "on a messageboard" is just a place, not a context.

I must completely misunderstand what "context" means, then. I don't see how I failed to answer what the context of the question is. But then I also don't see how I need to manufacture some outside context to get a person's answer. Reading this question right here on this forum *is* the context.

Bullgrit

Janx · Aug 26, 2013

Bullgrit said:
This wasn't a trick question. There was no trickery or misdirection, and no point to be made. No one who answered either way should feel in anyway tricked. It's not like I had the "correct" answer, and just wanted to spring it on anyone who answered "wrong."

"Trick" being the only adjective I could think of to apply to it. The actual goal of the querant was NOT the objective of the question.

if "Have you stopped beating your wife" is a trick question, and "What is your favorite colour" is not a trick question, then "Is Earth a Sphere" falls closer to the trick bucket than not.

As an experiment to see how Janx responds differently than Umbran, it's fine.

As a style of asking questions of normal conversation or of answering them, it indicates some other communication lessons to consider (as I wrote about later).

Bullgrit said:
I must completely misunderstand what "context" means, then. I don't see how I failed to answer what the context of the question is. But then I also don't see how I need to manufacture some outside context to get a person's answer. Reading this question right here on this forum *is* the context.

I certainly get that the Misc Forum on EN World is where thought experiment or sciency questions get asked. thus, the context of you asking "Is Earth a Sphere" on this forum different than if you had asked it in a conspiracy theory forum (where the flat-earthers might troll).

Is Earth a sphere?

Is Earth a sphere?

Yes

No

Morrus

Well, that was fun

gamerprinter

Mapper/Publisher

Umbran

Mod Squad

Hand of Evil

Hero

Janx

Hero

darjr

I crit!

Janx

Hero

tomBitonti

Adventurer

Bullgrit

Adventurer

Janx

Hero

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